(1. 銅陵學院 機械工程學院，銅陵 244061；
2. 東北大學 軋制技術(shù)及連軋自動化國家重點實驗室，沈陽 110819；
3. 安徽工業(yè)大學 冶金工程學院，馬鞍山 243032)
摘 要: 采用退火態(tài)軋制銅箔為原料，進行晶粒尺寸效應(yīng)的箔軋實驗和晶體塑性有限元模擬。基于率相關(guān)晶體塑性理論，開發(fā)用戶材料子程序(UMAT)，建立軋制銅極薄帶的晶體塑性有限元模型，改進Voronoi圖種子生成的隨機性，建立反映晶粒形貌、晶界不規(guī)則性的多晶極薄帶幾何模型，并編寫賦予多晶取向的算法，用以控制多晶取向及織構(gòu)分布，研究晶粒尺寸效應(yīng)對其變形機制的影響。結(jié)果表明：在銅極薄帶中尺寸較小晶粒中產(chǎn)生的剪切帶相對于尺寸較大晶粒中產(chǎn)生的要均勻，可較好地減小變形局部化；不同晶粒尺寸銅極薄帶的滑移系啟動和累積滑移存在顯著差異，啟動的滑移系隨晶粒尺寸的減小而增多；表層晶粒和內(nèi)部晶粒的約束差異導(dǎo)致變形后晶粒取向主要繞橫向(TD)進行旋轉(zhuǎn)，旋轉(zhuǎn)角度和極點分散度隨晶粒平均尺寸的減小而減小。箔軋實驗和模擬得到的軋制 力-晶粒尺寸曲線基本一致，即晶粒取向?qū)堉屏Φ挠绊戨S晶粒平均尺寸的減小而減弱。
關(guān)鍵字: 極薄帶軋制；多晶模型；晶體塑性有限元；晶粒尺寸效應(yīng)
（1. School of Mechanical Engineering, Tongling University, Tongling 244061, China;
2. State Key Laboratory of Rolling and Automation, Northeastern University, Shenyang 110819, China;
3. School of Metallurgical Engineering, Anhui University of Technology, Maanshan 243032, China）
Abstract:Annealed pure copper foils were taken as raw materials, and after the processes of foil rolling, the grain size effect was studied by foil rolling experiment and crystal plasticity finite element simulation. A user defined material subroutine (UMAT) developed based on the rate-dependent crystal plasticity theory embedded into the finite element software to analyze the grain size effect on micro-scale deformation mechanism of rolling polycrystalline copper ultra-thin strip. The random generating of the Voronoi diagram seeds was improved. The polycrystalline ultra-thin strip geometry model was created by constructing a new seeds generation algorithm, which can express the shape of the grains and the irregular grain boundaries. An algorithm to describe the grain orientation and texture distribution was introduced by adjusting the modeling parameters. The results show that the shear bands in small grain size are more uniform than those in large grain size which could effectively reduce the rolling deformation locality. The activity of slip system and accumulated slip are significant different in the foils with different grain sizes, and the activity of slip systems increases with decreasing grain size. The rotate of crystallographic orientation mainly around the transverse direction attributes to the different constraint of surface grain and internal grain, and the growth of rotation angle and dispersion degree decreases with decreasing grain size. The effect of grain orientation on roll force is weakened with decreasing grain size, and the roll force-grain size curves from the simulation agree well with the rolling experimental results.
Key words: foil rolling; polycrystalline model; crystal plasticity finite element; grain size effect
